1. Field Of The Invention
The present invention relates to the field of integrated circuits.
Specifically, the present invention relates to sockets for receiving integrated circuits and the like.
2. Description of Related Art
Many modem electronic circuit boards contain on-board read-only memory, typically provided as an erasable programmable read-only memory (EPROM). An EPROM provides permanent storage for configuration information or processing logic (i.e., firmware) that is used by the circuit board during normal operations or in a testing mode. One advantage of using an EPROM on a circuit board is that the operation of the circuit board can be customized without the need for jumpers, switches, or other hardware selection devices. Further, permanent memory storage is provided on the EPROM for storage of driver software used for controlling the operation of various resources or systems provided by the circuit board. The use of an EPROM device is convenient in that upgrades or enhancements to this driver software may be accomplished by replacing the EPROM device with a replacement containing the upgraded firmware. In this manner, the operation of a circuit board may be customized or upgraded.
One disadvantage in using a standard EPROM device for customizing a circuit board is that the EPROM must be removed from the board and replaced by another EPROM device containing the upgraded configuration information or firmware. Because the EPROM device must be removable, circuit board designers typically provide a socket into which an EPROM device may be removably inserted. In a conventional system, the socket pinouts are identical to the pinouts for the integrated circuit that is plugged into the socket. For that reason, conventional systems are limited to use of a single type read-only memory device for a given socket pinout configuration. Another disadvantage of conventional systems using EPROM devices is that the content of the EPROM devices cannot be modified without removing them from the circuit. The steps of removing an EPROM device and replacing the device with an upgraded EPROM requires field service support or user intervention. Sometimes errors are introduced in this process.
New non-volatile memory technology has given rise to new circuit board applications. Once such new technology is flash memory. Flash memory is a non-volatile memory technology wherein memory contents persist after power down; but, unlike an EPROM device, flash memory can be reprogrammed without removing the device from the circuit. Flash memory mitigates some of the limitations inherent in the use of EPROM devices. For example, configuration information or software resident within a flash device may be modified and permanently written into the flash device without removing the device from a circuit board. The problems inherent in removal and reinstallation of a modified EPROM device are thereby eliminated.
It is convenient in conventional systems to provide a means by which more than one type of read-only memory device may be installed in a socket on a circuit board. Having such a mechanism would allow a user to install either an EPROM device or a flash device into the same socket on a circuit board. In this manner, a particular circuit board could support either type of permanent storage device. However, the use of a single socket for multiple types of non-volatile memory devices is not provided in the prior art. Because the pinouts for an EPROM or other read-only memory device are different from the pinouts of a flash device, a single socket in conventional systems cannot support multiple types of permanent storage devices.
Thus, a better means and method is needed for allowing multiple types of permanent storage devices to be installed in a single socket on a circuit board.